Daily Crop Growing Degree-Day Accumulations
Development of crops in Illinois can be tracked and projected by maintaining an account of the "heat" accumulated during each growing season. This process involves a comparison of daily maximum and minimum temperatures to a base temperature, specific for a particular crop, above which development will occur.
The following pages result from a scientific effort by the Illinois State Water Survey, using weather data collected on a daily basis, to provide up-to-date information about crop development in Illinois. Computer algorithms have been developed for tracking crops with two different development thresholds.
Users begin by selecting the closest weather station to their location and the crop type of interest. Crop degree-day accumulations are tied to planting date, etc. One- and two-week degree-day projections are also included. Maps of degree-day totals and projections for the entire state are produced using specific planting dates to view trends within a region as a season progresses.
All degree-day information is computed from data collected through the day just prior to the one when a user accesses the system. In general, up-to-date information should be available by 4:00 a.m., seven days a week.